If power shots overall become much more costly to stamina, then a raise in power is balanced by default. People would hesitate to abuse the strikes if they knew there was a consequence to be paid, and even then, landed, blocked and whiffed strikes would become weaker over time maintaining the decision ratio.
there is no reason a person should be able to walk through perfectly timed counters and flush shots...especially when they follow that by dropping/ dazing you with a random strike.